Those symptoms are not unlike those of chikungunya, also spread by mosquitoes, and a virus that first appeared in Mexico in June of last year. One year later and there were an estimated 1,436 cases in 10 states, of which Guerrero led with 839, followed by Oaxaca and Chiapas.

Few people die from chikungunya and officially there have been no deaths in Mexico. Unofficially, however, there have been deaths reported in Guerrero and Oaxaca.